The "pear-shaped" bladder.

Abstract

A pear’s shape (Fig. 1) is used to describe the contour deformity of the bladder produced by symmetric compression from pelvic pathology [1, 2]. Originally described in the context of trauma and associated pelvic hematoma [1], the appearance was reported on urographic and cystographic images (Fig. 2) [1, 3, 4]. Additional descriptors in the literature conveying a similar impression of the altered contour include the ‘‘tear-drop’’ and ‘‘gourd-shaped’’ bladder [3, 5]. The pear-shaped configuration of the bladder has been associated with a broader differential diagnosis including symmetric extraperitoneal processes such as lymphadenopathy, pelvic lipomatosis, psoas muscle hypertrophy, and enlarged collateral vessels secondary to inferior vena cava obstruction [1–5]. Mass effect from adjacent fluid collections (e.g., blood, lymph, or urine) or iliac aneurysms can also produce this appearance [1, 2], albeit with greater asymmetry. Currently, the radiologist is more likely to encounter this appearance at cross-sectional imaging, where the compressing pathologic process may be more evident [Fig. 3A, B].